Hemagglutinin and neuraminidase are surface attachment proteins of the influenza virus. There are several areas related to these surface proteins which still need to be explored: 1) The distribution of the hemagglutinin and neuraminidase on the viral surface are not yet clear due to the variety of their shapes. 2) The conformational change of hernagglutinin at low pH, which has been indirectly illustrated in other studies. 3) Why the influenza viruses from different species vary in their virulence and their requirements for cleavage of the hemagglutinin molecule. 4) Finally, the interaction of the hemagglutinin with antibody. The examination of influenza virus with high resolution cryo-SEM in combination with backscattered electron (BSE) imaging would be extremely informative from several different perspectives that are related both to antigenic recognition and pathogenesis.